AtomicReference测试

qui910 · qui910 · commit 626eed8e1ab9 · 2020-07-08T16:40:45.000+08:00
diff --git a/src/main/java/com/prd/concurrent/AtomicReferenceTest.java b/src/main/java/com/prd/concurrent/AtomicReferenceTest.java
@@ -0,0 +1,76 @@
+package com.prd.concurrent;
+
+import java.util.Objects;
+import java.util.concurrent.atomic.AtomicReference;
+
+/**
+ * AtomicReference测试
+ */
+public class AtomicReferenceTest {
+
+    public static void main(String[] args) {
+
+//        normalString();
+
+        beanTest();
+    }
+
+    /**
+     * 常规使用测试
+     */
+    private static void normalString() {
+        String a = new String("a");
+        String b = new String("b");
+        String c = new String("a");
+        AtomicReference<String> reference = new AtomicReference<>(a);
+        System.out.println("初始值为："+reference.get());
+        // 输出为fasle，说明这里使用的引用地址比较，而非对象的equals
+        System.out.println("使用c和b是否更新成功："+reference.compareAndSet(c,b));
+        System.out.println("使用a和b是否更新成功："+reference.compareAndSet(a,b));
+    }
+
+    /**
+     * 测试equals相等的变量，是否影响cas
+     * 结果：
+     初始值为：a1
+     a1和c1是否相等：true
+     使用c1和b1是否更新成功：false
+     使用a1和b1是否更新成功：true
+       分析：
+     这里的cas使用的是内存中的偏移量做的判断，与equlas无关
+     */
+    private static void beanTest() {
+        Student a1 = new AtomicReferenceTest().new Student("a1");
+        Student b1 = new AtomicReferenceTest().new Student("b1");
+        Student c1 = new AtomicReferenceTest().new Student("a1");
+
+        AtomicReference<Student> reference1 = new AtomicReference<>(a1);
+        System.out.println("初始值为："+reference1.get().name);
+        // 输出为fasle，说明这里使用的引用地址比较，而非对象的equals
+        System.out.println("a1和c1是否相等："+c1.equals(a1));
+        System.out.println("使用c1和b1是否更新成功："+reference1.compareAndSet(c1,b1));
+        System.out.println("使用a1和b1是否更新成功："+reference1.compareAndSet(a1,b1));
+    }
+
+
+    class Student {
+        String name;
+
+        public Student(String name) {
+            this.name = name;
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (!(o instanceof Student)) return false;
+            Student student = (Student) o;
+            return Objects.equals(name, student.name);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(name);
+        }
+    }
+}
